Spathaspora elongata C.Y. Chai & F.L. Hui, 2020

Lv, Shi-Long, Chai, Chun-Yue, Wang, Yun, Yan, Zhen-Li & Hui, Feng-Li, 2020, Five new additions to the genus Spathaspora (Saccharomycetales, Debaryomycetaceae) from southwest China, MycoKeys 75, pp. 31-49 : 31

Spathaspora elongata C.Y. Chai & F.L. Hui sp. nov. Figure 2

Type.

China, Yunnan Province, Jinghong City, Mengyang Town, in rotting wood from a tropical rainforest, August 2018, K.F. Liu & Z.W. Xi (holotype, NYNU 18115T preserved in a metabolically-inactive state), ex-holotype: CICC 33353; CBS 16002.

Etymology.

Elongata refers to the elongate ascospores of this yeast.

Description.

After 3 days of culture in YM broth at 25 °C, the cells are ovoid (3-4 × 3-7 μm) and occur singly or in pairs (Fig. 2a ). Budding is multilateral. Sediment is formed after a month, but a pellicle is not observed. After 3 days of growth on YM agar at 25 °C, colonies are white to cream-coloured, butyrous and smooth with entire margins. After 14 days at 25 °C, on Dalmau plate culture on CM agar, pseudohyphae are present, but true hyphae are not formed (Fig. 2b ). Sporulation occurs on dilute (1:19) V8 agar after 14 days at 25 °C. Unconjugated asci are formed from single cells with one elongated ascospore which are tapered and curved at the ends (Fig. 2c ). Glucose, galactose, maltose and sucrose are weakly fermented. Xylose fermentation is absent using Durham tubes, but ethanol is produced from xylose when determined with alcohol oxidase and peroxidase tests. Glucose, d-ribose, d-xylose, d-arabinose, sucrose, maltose, trehalose, methyl α-d-glucoside, cellobiose, salicin, arbutin, inulin, ribitol, d-glucitol, d-mannitol, 2-keto-d-gluconate, succinate, citrate and ethanol are assimilated. No growth occurs with galactose, l-sorbose, d-glucosamine, l-arabinose, l-rhamnose, melibiose, lactose, raffinose, melezitose, glycerol, erythritol, xylitol, galactitol, myo -inositol, d-glucono-1, 5-lactone, 5-keto-d-gluconate, d-gluconate, d-glucuronate, dl-lactate or methanol. For the assimilation of nitrogen compounds, growth on ethylamine, l-lysine, glucosamine or d-tryptophan is present, whereas growth on nitrate, nitrite, cadaverine, creatine, creatinine or imidazole is absent. Growth is observed at 37 °C but not at 40 °C. Growth in the presence of 1% acetic acid is present, but growth in the presence of 10% sodium chloride (NaCl) plus 5% glucose and 0.01% cycloheximide is absent. Starch-like compounds are not produced. Urease activity and diazonium blue B reactions are negative.

Additional isolates examined.

China, Yunnan Province, Jinghong City, Mengyang Town, in rotting wood from a tropical rainforest, August 2018, K.F. Liu & Z.W. Xi, NYNU 181112, NYNU 181120 and NYNU 181158.

Notes.

Four strains, representing Sp. elongata , clustered in a well-supported phylogenetic clade that is closely related to Sp. mengyangensis , another new species proposed in this paper and C. subhashii . The nucleotide differences between Sp. elongata and Sp. mengyangensis were 2.5% substitutions in the D1/D2 domain and 5.2% substitutions in the ITS region ( Groenewald et al. 2016). Similarly, Sp. elongata and C. subhashii showed differences of 3.9% substitutions in the D1/D2 domain and 5.9% substitutions in the ITS region ( Groenewald et al. 2016). Physiologically, Sp. elongata can be differentiated from its close relative, Sp. mengyangensis , based on its growth in citrate and the presence of 1% acetic acid, which are present for Sp. elongata and absent for Sp. mengyangensis . Moreover, Sp. elongata weakly ferments glucose, galactose, maltose and sucrose and grows at 37 °C, but Sp. mengyangensis does not.

Figures

Figure 2. Morphology of Spathaspora elongata (NYNU 18115, holotype) a budding cells on YM broth after 3 d b Pseudohyphae on CM agar after 14 d c ascus and ascospore (arrow) on dilute V 8 agar after 14 d. Scale bars: 10 μm.